A next-generation mobile communication system (for example, LTE: Long Term Evolution) following the IMT-2000 (International Mobile Telecommunication-2000) system is configured to set up an access bearer for transmitting user plane (U-plane) data between a RAN (Radio Access Network) node (for example, radio base station eNB) and a core node (for example, SGW: Serving Gateway).
Such access bearer is formed by GTP (GPRS Tunneling Protocol) tunnel.
Also, in the LTE mobile communication system, a radio bearer is configured to be set up between a mobile station UE and the RAN node.
Furthermore, in the LTE mobile communication system, an EPS (Evolved Packet System) bearer is configured to be set up between the mobile station UE and the core node.
When a mobile station performs a handover from a handover-source radio base station to a handover-target radio base station, a GTP tunnel is configured to be set up between the handover-source radio base station and the handover-target radio base station. The handover-source radio base station and the handover-target radio base station are under the control of the same core node. Then, the user plane data corresponding to each access bearer is configured to be forwarded from the handover-source radio base station to the handover-target radio base station via the GTP tunnel.
However, in the LTE mobile communication system, when such handover as described above is performed, the GTP tunnels corresponding to all the access bearers set up between the handover-source radio base station and the core node are configured to be set up, regardless of whether or not user plane data to be forwarded from the handover-source radio base station to the handover-target radio base station exists. Thus, the system has a problem of wastefully using resources.